A kind of method for continuously synthesizing white carbon black and sodium fluoride

Abstract

The invention provides a method for continuously synthesizing silica and sodium fluoride, comprising the following steps: synchronously pumping a soda ash solution and a sodium fluorosilicate solution into a feed port of a tubular reactor to form a mixed solution, and the mixed solution flows through the tubular reaction The reactor was reacted at 75-88°C for ≥5min, and the reacted liquid flowed out from the discharge port of the tubular reactor. After the reaction, the liquid was exhausted, and the solid-solid was separated to obtain the crude product of sodium fluoride and the slurry containing the crude product of white carbon black. , washing, purifying and drying the crude sodium fluoride product to obtain a finished product of sodium fluoride; subjecting the slurry containing the crude silica product to solid-liquid separation, washing and drying to obtain a finished silica product, the present invention provides a first A method for continuous production of high-purity, high-activity white carbon black and high-quality sodium fluoride. The indicators of the obtained silica far exceed the current requirements for the first-class precipitation method, with BET>240m 2 / g, stable quality, narrow particle size distribution, can partially replace fumed silica, is a high-end silica product.

Description

technical field [0001] The invention relates to a method for continuously synthesizing white carbon black and sodium fluoride, and belongs to the field of chemical industry. Background technique [0002] Sodium fluoride is used as a phosphating accelerator in the coating industry to stabilize the phosphating solution, refine the phosphating, and improve the performance of the phosphating film. Blocking Al, which has a very harmful negative catalytic effect, in the phosphating of aluminum and its alloys 3+ , Make the phosphating proceed smoothly, wood preservatives, agricultural insecticides, brewing industry fungicides, pharmaceutical preservatives, welding fluxes, alkaline zincate galvanizing additives and enamel, paper industry and so on. [0003] Silica is mainly used in colored rubber products to replace carbon black for reinforcement to meet the needs of white or translucent products. Silica also has super adhesion, tear resistance and heat resistance and aging resist...

AI Technical Summary

Problems solved by technology

[0004] At present, there are two types of mature white carbon black processes: using silicon tetrachloride as raw material, hydrogen-oxygen combustion hydrolysis gas-phase process, which is expensive; the process of using quartz sand as raw material to synthesize water glass, and then neutralizing with acid precipitation method process, the BET of silica synthesized by this process is not high, and the particle size distribution is wide, which basically cannot meet the requirements of high-end products

The recently proposed water glass carbonization method still belongs to the precipitation process, and the quality of its products has not been greatly improved compared with the traditional method of neutralizing water glass with acid.

However, the presence of a large amount of by-product hydrochloric acid in fumed silica and the high price of raw materials have restricted the competitiveness of the product, and the quality and performance of silica obtained by sodium silicate precipitation are poor.

[0005] In the industry, fluorosilicic acid, sodium fluorosilicate and soda ash are often used to produce sodium fluoride and co-produce white carbon black; the reaction batch method is used to synthesize sodium fluoride, and the batch reaction is adopted. Since sodium fluoride is in the reactor Large changes in concentration will lead to scarring of the reactor wall, resulting in increased thermal resistance, reduced heat transfer efficiency, often resulting in interruption of the reaction, and at the same time the quality of the obtained silica is low

[0006] The patent (CN108751227A) discloses a production process using sodium fluorosilicate to produce sodium fluoride and co-produce white carbon black. Specifically, a new type of ultrasonic reactor is used to effectively prevent the reaction product from scarring on the reactor wall, and the reactor heat The resistance is small, the heat transfer efficiency is high, and the intermittent feeding can be realized without interruption, but the continuous production cannot be realized, and the problem of low quality of silica is not solved at the same time

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